lathes.co .uk says the 20″ is how they named their machines by the table travel. I assume X axis?

In Andrew’s photo the cut is made by raising the table, cutter is cutting downwards which is better that doing it on the other side and having the cutter try to lift the work off the table.

Vertical travel on my universal Adcock and Shipley 2E is also 16″. But of more importance is the spindle centre to table distance. For the plain (non-swivelling table) 2E the distance is 19″, but on the universal it is 16″. If we assume it is 16″ then minus 14.5″ leaves 1.5″, which means the cutter diameter has to be 3″ or less. I think most 5DP cutters are going to be comfortably larger than 3″ diameter; 3-3/4″ seems very common. My gears had 72 teeth, so easy indexing every 5 degrees. Incidentally I make the OD of a 5DP gear with 71 teeth to be 14.6″.

The 20″ dimension on the Archdale will be X-axis travel. On my 2E X-axis travel is 23″, not much more than half that on the Bridgeport, despite the horizontal weighing nearly twice as much.

Larry: It’s not a silly question. As JasonB says the cut was put on by raising the table and then lowering it ready for indexing the next cut so the cutting forces are downwards. Although not visible there is support under the gear near the periphery. Each tooth required 22 turns of the handle, followed by 22 turns the other way. I am building two engines, so four gears, and a mate who is building the same engine just happened to have his gear blanks ready at the same time. So six gears in total. It keeps you fit! I have a video of one tooth being cut but don’t know how to convert it to a file that I can post on here.

I am building two 4″ scale Burrell single crank compound engines:

Andrew

Thank you, raw file sent via WeTransfer.

Andrew

This is Andrew getting his daily workout on the Adcock & Shipley, I can see why he advocates cutting each tooth in one pass.

I bet you could murder a few pints after all that !!